Bolt size needed for mounting FEL on 1710?

[Kopierguy]

I have a new to me Ford 1710 and I am in the process of installing a FEL. It will attach to the 4 mounting holes on each side of the tractor. I am sure those holes have metric threads and if someone could tell me what diameter and thread pitch is needed. Thanks

 

[nsmithnd]

(Messicks) shows the following...

 

[Kopierguy]

(Messicks) shows the following...

View attachment 324104

Thanks for the quick response. I think I will use a 40MM length since I have enough thread depth in the casting. I bookmarked Messicks for future needs. My local bolt supply will be open Monday and hopefully they will have what I want.